Hi I am new to this and I would like to know what CAD files are used for, like can I download these to a CNC machine or 3D printer and will it either cut the or print what is on the file or is it just to look at.
Just like a word file is used to store a word document, a CAD file stores the model data. There are some steps you will need to follow for using the file on a 3D Printer:
> Open and save the CAD file as a .stl file
> Open the file on slic3r and generate the g-code
> Run the g-code on prontoface to start your print
the library page (the page linked to from the new / popular list) will tell you whether it was modelled in autocad / inventor / solid edge / solidworks / pro-engineer etc. you need these softwares to open the dedicated file format. the software may also be able to import other cad systems' file formats.
sometimes the files are already saved as .stl files, saving you time to get it to the 3d printer.